Jerusalem — Fifteen years of Israeli occupation of the Sinai Peninsula ended April 25 with little fanfare and much Israeli reticence.
Israeli Defense Minister Ariel Sharon told Israeli soldiers this would be Israel's last territorial concession and promised to accelerate Israeli settlements in the occupied West Bank and Gaza.
The Israeli flag was lowered and the Egyptian banner raised at Sharm el Sheikh, at the southern tip of the Sinai, and at Rafah in the north. Israeli troops evacuated the last holdout settlers from the area. Because there still are minor border disputes, Israel established the border where it claims it should be, pending arbitration.
There were last-minute reassurances to Israeli Prime Minister Menachem Begin from Egyptian President Hosni Mubarak that the peace would last. Mr. Begin also sent a letter to Jihan Sadat, widow of the Egyptian leader whose bold visit to Jerusalem in November 1977 laid the groundwork for the eventual return of Sinai and of peace between the two countries.
But for the Israeli audience, the government message was clear: Sinai was the end of the line in bargaining away Israeli land.
''In Sinai, in Yamit, we have reached the red line of our concessions,'' Mr. Sharon said in an ''order of the day'' for April 25 read at military bases throughout the country.
''We shall turn to strengthening our security, to our development in every sphere. We shall turn to increasing and consolidating our settlements on the Golan Heights, in Judea, Samaria (the West Bank), and the Gaza district.''
Mr. Sharon, who managed the Israeli withdrawal and apparently tried unsuccessfully to persuade Mr. Begin to delay the evacuation, added that: ''The ruins of Yamit will also serve as a testimony that we have done everything imaginable to keep to the peace agreement, so that our children will not point an accusing finger at us and say we missed an opportunity. No Arab army has ever succeeded -- or ever will succeed -- in destroying an Israeli city.''
By all accounts, Israel is in an extremely sensitive mood. The evacuation and leveling of Yamit -- which received extensive television coverage April 23 -- caused most Israelis to react by vowing not to abandon any of the West Bank or Gaza cities. Israeli leaders promise to continue reassuring their population that this is the last concession.
The country is decorated with Israeli flags and blue and white bunting this week. But it is in observance of Independence Day April 27, not for the Camp David treaty.
''The festivity here on the day of independence is going to have a sour, bitter taste, especially for those persons involved with this Sinai experience, '' a government official predicts. ''There will be little joy.''
What lies ahead for Israel in its normally difficult relations with its Arab neighbors is uncertain. According to some observers, the evacuation of the Sinai shows that Camp David is alive and well -- and now is the time to push for Palestinian autonomy as outlined in the second phase of the Camp David agreements. Conversations with Israeli strategists the past week has produced this agenda for the months ahead:
* Normalization: Besides providing for the return to Egypt of Sinai, Camp David set out a path of normalization of relations between the two countries. Israeli officials, however, complain that so far the framework for normalization may be in place but the substance is lagging far behind.
* Palestinian autonomy: Israel is still officially pushing for implementation of Palestinian autonomy as set out in Camp David. But its settlement policy in occupied territories indicates that ultimately Israel intends to annex large chunks -- if not all -- of the West Bank and Gaza.
''We can see on the horizon the signs of a very hard political battle over the future of th territories still under Israeli occupation,'' wrote the Palestinian newspaper al-Fajr April 25.
* The Palestine Liberation Organization: Both within Israeli borders and outside them, Israel is waging an increasingly tense struggle against the PLO. Within Israel, the Begin government, through its civil administrator for the occupied territories, Menachem Milson is attempting to create a pro-Israeli Palestinian power structure through a system of ''village leagues.'' Palestinians who support the PLO have been removed from office in three cities, and harsh disciplinary measures have been introduced in an effort to crush Palestinian nationalism.
Meanwhile, almost all Israeli offcials -- including members of the opposition Labor Party -- reckon that a battle with the PLO in Lebanon could come at any time. Last week's Israeli air raids into Lebanon set the stage for a battle if the PLO retaliates.